Channeling measurements in As-doped Si

Channeling-effect measurements with 1.8-MeV helium ions on silicon samples doped with arsenic to concentrations up to 1.5×1021 atoms/cm3 indicate that greater than 90% of the arsenic atoms occupy substitutional lattice sites. A narrowing of the angular-yield profile is observed for arsenic concentrations in excess of 1020 atoms/cm3. A movement of arsenic atoms off substitutional lattice sites is observed after bombardment with MeV helium ions. The initial rate of movement (1017 As atoms/cm/μC) is independent of the arsenic concentration. In arsenic-diffused samples subjected to prolonged heat treatment at temperatures between 650–900°C an increase is seen in both silicon and arsenic aligned yields. The relative increase in the arsenic aligned yield is less than the relative increase in sheet resistance.